Cyclooligomerization



United States Patent CYCLOOLIGOMERIZATION Marvin A. McCall and Harry W. Coover, Jr., Kingsport,

Tenn., assignors to Eastman Kodak Company, Rochester, N.Y a corporation of New Jersey No Drawing. Filed May 13, 1965, Ser. No. 455,636

9 Claims. (Cl. 260-666) ABSTRACT OF THE DISCLOSURE This invention relates to a novel chemical process and more particularly to a novel process for the production of cyclic oligomers from 1,3-dienes and to novel catalyst systems which are useful in the process.

Cyclic oligomers have been prepared from 1,3-dienes by a number of methods. For example cyclooctadienes and 4-vinylcyclohexenes have been prepared by the therand 4-vinyl-cyclohexenes have been prepared by the thermal dimerization of 1,3-dienes and these and other cyclic oligomers have been prepared by contacting a 1,3-diene with complexed zerovalent nickel. These known processes are characterized by one or more serious deficiencies. Thus, the predominant products from the thermal dimerization of 1,3-dienes are the 4-vinylcyclohexenesibut the highly desired cyclooctadienes are obtained in low yields and conversions. The complexed zerovalent nickel catalysts which have heretofore been employed in cyclooligomerization processes are extremely unstable and therefore require special handling procedures and, in addition, catalyze the formation of other products, thus decreasing the yield of the highly desired cyclooctadienes.

We have discovered a novel catalyst system for cyclooligomerization processes which, when employed in accordance with the process of our invention, is highly selective'for the production of cyclooctadienes from 1,3- dienes and, in addition, is exceptionally stable and therefore does not require the special catalyst handling procedures which have heretofore been needed with zerovalent nickel catalysts. Our invention depends, in part, upon our discovery that solutions of complexed zerovalent nickel in a large} excess of the organo-phosphorous complexing ligand are unexpectedly stable when exposed to normal environmental conditions and that such solutions are also unexpectedly effective for the production of cyclooctadienes from 1,3-dienes when employed in accordance with the process of our invention.

The novel catalyst systems within the scope of our invention are those solutions of complexed zerovalent nickel in an excess of the organo-phosphorous complexing ligand in which the mole ratio of excess ligand to zerovalent nickel is at least 10:1 and are preferably such solutions in which the mole ratio of excess ligand to zerovalent nickel is at least 24: 1.

The preferred organo-phosphorous compounds for use as complexing ligands and for use as solvents in preparing our novel catalyst systems are tri(hydrocarbyl) phosphines and tri(hydrocarbyl) phosphites. The useful tri(hydrocarbyl) phosphines can be represented by the formula:

R 1 and the useful tri(hydrocarbyl) phosphites can be represented by the formula:

in which R is an aliphatic or aromatic hydrocarbyl group. The hydrocarbyl group R preferably has from 1 to 10 carbon atoms. Examples of the aliphatic groups which R can represent are alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, etc. Examples of the aromatic groups which R can represent are the; mononuclear ca-rbocyclic aryl or aralkyl groups such as phenyl, o-tolyl, m-tolyl, p-tolyl, benzyl, xylyl, etc. -R, when alkyl, is typically methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, isobutyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, etc. Examples of the alkenyl substituents which R can be include vinyl, l-propenyl, Z-butenyl, 4-pentenyl, l-hexenyl, 3-heptenyl, l-octenyl; 2-nonenyl; 5-decenyl, etc. R, when alkynyl, is typically ethynyl, l-propynyl, 3-butynyl, 3-pentynyl, l-hexynyl, 4-heptynyl, l-octynyl, 2-nonynyl, S-decynyl. R, when cycloalkyl, is typically cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, etc., and, when cycloalkenyl, is typically cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, etc.

The complexed zerovalent nickel component of our novel catalyst system can be represented by the formula:

3 )z when the complexing ligand is a tri(hydrocarbyl) phosphine and by the formula:

when the complexing ligand is a tri(hydrocarbyl) phosphite. The hydrocarbyl groups, R, in the preceding formulae can be the same or different and can be aliphatic or aromatic as explained hereinbefore.

The novel catalyst system of invention can be prepared by reducing a nickel compound in the presence of the complexing ligand and then adding suflicient complexing ligand to obtain the desired proportion of excess ligand. Alternatively, the reduction of the nickel compound can be carried out in the presence of the entire amount of complexing ligand. In either event, the resulting catalyst solution should contain at least 10 moles of excess ligand per mole of zerovalent nickel and preferably at least 24 moles of excess ligand per mole of zerovalent nickel. As hereinbefore stated, the novel catalyst systems of our invention are unexpectedly stable and are especially useful in the manufacture of cyclooctadienes such as 1,3- cyclooctadienes and 1,5-cyclooctadienes from 1,3 dienes in that the catalyst system is more selective for the highly desired cyclooctadienes than other known catalyst systems.

Examples of the tri(hydrocarbyl) phosphine compounds which are useful as the complexing ligands and as the catalyst solvents are compounds such as trimethyl phosphine, triethyl phosphine, tripropyl phosphine, tridecyl phosphine, triphenyl phosphine, tri(o-tolyl) phosphine, tricyclobutyl phosphine, tri(l-cyclopentenyl) phosphine, tri(Z-pentynyl) phosphine, etc. Examples of the tri(hydrocarbyl) phosphite compounds which are useful as complexing ligands and as catalyst solvents are compounds such as trimethyl phosphite, tripropyl phosphite, tributyl phosphite, trioctyl phosphite, triphenyl phosphite, tri(o-tolyl) phosphite, tricyclobutyl phosphite, tricyclopentyl phosphite, triethynyl phosphite, tri(Z-cyclohexenyl) phosphite, etc.

The process of our invention is carried out by contacting a 1,3-diene with the novel catalyst system of our invention. Included among the 1,3-dienes which are useful in the process of our invention are those which have been employed in known cyclooligomerization processes. Compounds such as 1,3-butadiene; isoprene; piperylene, chloroprene; 2,3-dichloro-1,S-butadiene; 2,3-dimethyl- 1,3-butadiene; etc. are among those which are useful in our process.

The reaction is generally carried out at a temperature of about 20 C. to about 225 C. and preferably at about 80 C. to about 175 C. The reaction is preferably cardesired cyclooctadienes as the novel catalyst systems of our invention.

The following example illustrates the process of our invention.

ried out in the liquid phase and the reaction pressure is EXAMPLE 1 therefore equal to or greater than the vapor pressure of Dry nickel acetylacetonate (2.6 g., 0.01 mole) was d1sthe reaction mixture at the reaction temperature. In gensolved in 50 cc. of tri(o-tolyl)phosphite. Triethyl alumieral, preferred pressures range from about atmospheric num (2.5 g., 0.02 mole) was slowly added to this mixture pressure to super-atmosphere pressures of 150 atmoswith stirring to reduce the nickel acetylacetonate to zeropheres or more. The time required for the reaction usually valent nickel. The mixture was then diluted to 96 cc. wlth varies from about 10 minutes to several hours or more, tri(o-tolyl)phosphite. The resulting solut1on contained depending upon the reaction temperature. Especially suitabout 24 moles excess tri(o-tolyl)phosphite per mole of able reaction times range from about minutes to about nickel. Portions of this catalyst solution were then used 1n 2 hours. 15 manufacturing cyclooctadienes from 1,3-butadiene accord- The reaction can be carried out with or without an ing to the following procedure. The catalyst and 150 cc. added inert solvent. Among the useful inert solvents which (93 g., 1.73 moles) of butadiene were charged to a staincan be employed are ethers such as diethyl ether, etc.; less steel autoclave. The autoclave was heated to 130 C. aromatic hydrocarbons such as benzene, toluene, mesifor 2 hours. The composition of the reaction product was tylene, etc.; aliphatic hydrocarbons such as petroleum, determined by gas chromatography and the percent of naphtha, hexane, octane, etc.; and heterocyclic compounds butadiene conversion to cyclooctadiene and to other cyclic such as tetrahydrofuran. However, it is preferred to emoligomers was calculated based on the total weight of ploy no additional solvent, the large excess of complexing butadiene charged. A series of runs were made accordlng ligand serving as the reaction medium. to the above procedure, using diminishing amounts of the The catalyst concentration employed in the process of catalyst in successive runs. The results of the series of runs our invention can be widely varied. Catalyst concentraare summarized in Table 1, below.

TABLE I [oligomerization Results Obtained With Catalyst Prepared in Excess Tri-o-tolyl Phosphite] Aliquot Total Butadiene Cat. Cone. Total Percent Percent Percent Etlicieucy Run No. Cat. Wt. Cat. Moles, Ni Charged, Moles Ni/ Wt. Re- 4. V.C.H.1 C.O.D:2 C.D.'I.2

Soln., cc. Oomp., g. Mole action Conversion Conversion Convers10n g.OOD/ g.COD[ g. Butadiene Pr0d., g. g! Cat. Mole N1 12 1. 12. 5 10- 93 72. 5X10- 101. 0 11. 3 s7. 4 0 54. 0 6. 5X10 12 1.50 12.5x10 03 72.5 10 103.0 11.5 88.0 0 54.5 0 54 10 0 0.75 6.25X10-4 93 30.3)(10- 93.0 9.3 85.0 0 105.3 120x10 0 0.75 6.25X10- 9s 35.3)(10- 98.0 8.5 02.0 0 114.0 1a.7 10 3 0.378 3.125 10- 93 1s.2 10- 90.0 8.0 83.4 0.5 205.0 24.s 10 3 0. 378 3.125 10- 93 1s.2 10- 95.0 7.5 91.3 1.0 224.4 272x10 1 0.125 1.04 10 03 5 05 10 87.0 7.8 70.0 0.7 517.0 020x10 1 0.120 1. 04x10- 93 6. 05 10 89.0 0.1 70.5 1.5 585.0 711x10 0.063 0. 52x10- 93 3. 02 10 30.0 7.8 18.5 0.0 273.0 33.1 10

1 4 V.C.H.=4-viny1 cyclohexenc, percent is based on amount of butadiene charged.

3 C.D.T.=l,5,9-cycl0dodecatriene, percent is based on the amount of butadiene charged.

Total wt. yield COD the amount of butadiene charged.

(Percent conversion COD) (g. butadiene charged) ciency 2 C.O.D.=1,3- and 1,5-cyelooctadiene, percent is based on 4 Catalyst Effl- Total wt. of catalyst components tions of from about 2 10 mole of nickel per mole of 1,3-diene to about 75 l0 mole of nickel per mole of 1,3-diene are generally employed. However, higher or lower concentrations of nickel can be used and are often preferred. A preferred catalyst concentration range is from about 3 10 mole of nickel per mole of 1,3-diene to about 50 10 mole of nickel per mole of 1,3-diene.

The novel catalyst compositions of the invention are unexpectedly stable to the action of air and moisture and retain their activity after exposure to air or moisture for several hours. Known zerovalent nickel catalysts generally lose their activity after exposure to air or moisture for only a few minutes. The process of our invention is unexpectedly selective for the formation 'of cyclooctadienes, e.g. 1,3-cyclooctadienes and 1,5-cyclooctadienes.

The cyclooctadienes are produced in unexpectedly high conversions with unexpectedly high catalyst efficiences when our novel catalyst system is employed in accordance with the process of our invention. Thus, in a series of tests in which the novel catalyst system of our invention was employed in our cyclooligomerization process, catalyst efficiencies as high as 7l.1 10 grams of cyclooctadiene per mole of nickel were achieved. In a series of comparison tests the highest catalyst efficiency achieved for a known zerovalent nickel catalyst was 22.5 X10 grams of cyclooctadiene per mole of nickel. In addition, the known catalysts are not as selective f t e highly Total wt. of catalyst components A series of experimental runs employing a known cyclooligomerization catalyst were carried out in accordance with the procedure of Example 2, below, for comparative purposes.

EXAMPLE 2 Nickel acetylacetone (2.6 g., 0.01 mole) was dissolved in about 50 cc. of mesitylene. Tri(o-toly1) phosphite (7.0 g., 0.02 mole) was next added to the solution of nickel acetylacetonate in mesitylene with stirring. Tri-ethyl aluminum (2.5 g., 0.02 mole) was slowly added to the mixture to reduce the nickel acetylacetonate to zerovalent nickel. The resulting mixture was then diluted to 96 cc. with mesitylene. The concentration of nickel in the catalyst solution was thus the same as the concentration of nickel in the catalyst solution of Example 1. Portions of this catalyst solution were then used in the cyclooligomerization of butadiene according to the procedure of Example 1. Thus, a portion of the catalyst solution and 150 cc. (93 g., 1.72 moles) of butadiene were charged to a stainless steel autoclave. The autoclave was heated to C. for 2 hours. The composition of the reaction mixture was determined by gas chromatography and the percent conversion of butadiene to cyclooctadiene and to other cyclic oligomers was calculated based on the total weight of butadiene charged. A series of such runs were conducted using diminishing amounts of catalyst in succeeding runs. The results obtained are summarized in Table H, 2. The process of claim 1 in which the organo-phosbelow. phor us ligand is selected from the group consisting of:

TABLE II [Oligomerization Results Obtained With Catalyst Prepared in Mesitylene Solvent] Aliquot Total Butadiene Cat. Cone. Total Percent Percent Percent Efficiency Run No. Cat. Wt. Cat. Moles, Ni Charged, Moles Nl/ Wt. Re- 4. V.C.H. C.O.D. C.D.T. Soln., cc. Gomp., g. Mole actlon Conversion Conversion Conversion g. COD g. COD/ g. Butadiene Prod, g. g! Cat. Mole Ni 12 1. 5 12.5X10 4 93 72.5X10- 101. 2 8. 6 82. 4 6. 2 51. 612x10 6 0.75 6.25X10- 93 36BX10 96.0 6. 4 81.3 9. 6 101.0 12.5Xl0 3 0. 378 3.125 93 18.2X10- 94. 0 6. 1 74. 7 16. 4 184. 0 22.5X10 3 0. 378 3.125 10- 93 18.2X10 95.0 5. 8 75.0 17. 8 184. 5 22.5X10 2 0. 252 2.08X10- 93 12.1X10- 34. 0 13. 6 6. 4 2. 2 23. 6 2.86X10 1 0.126 1.04X10' 93 6.05X10 5 48. 0 18.5 9.6 7. 9 70.8 8.6)(10 l 4 V.C.H.=4-viny1 cyclohexene, percent is based on amount of butadienecharged. 2 C.O.D.=1,3- and 1,5-cyclooctadiene, percent is based on amount of butadiene charged: G.D.T.=1,5,9-cyclododecatr1ene, percent is based on amount of butadiene charged. 4 Catalyst Efliciency= (Percent conversion COD) (g. butadiene charged): Total wt. yield COD Total wt. of catalyst components =Total wt. cat. components.

A comparison of the stability of our novel catalyst sys- (a) tri(hydrocarbyl)phosphines and tern with known catalysts was made in accordance with (b) tri(hydrocarbyl)phosphites. t e P du f Exa ple bBlOW- 3. A cyclooligomerization process for the production of EXAMPLE 3 a cyclooctadiene from a 1,3-diene which comprises contactmg a 1,3-d1ene with a catalyst system comprising A Portion the t y selutlen from Example 1 2'5 zerovalent nickel complexed with an organo-phosphorus was Placed a 50 beaker and Q to 3 complexing ligand and containing an excess of at least 24 hours. A portlon of the catalyst solution prepared in Exmoles of said ligand per mole of nickel; said organo mp 16 2 was placed m a separate 50 beaker and also phosphorus ligand being selected from the group consistexposed to air for 3 hours. Experimental runs employing the exposed catalysts were carried out according to the procedures of Examples 1 and 2. The conversion of 1,3- butadiene to cyclooctadiene was only 0.1 percent (trace) (b) tn(hydrf:arby1 )PhSP1{1teS when 1,3-butadiene was subjected to cyclooligomerization and Sald contactmg bemg earned out at a temperature of using the catalyst prepared according to the method of about to about and a Pressure of P to Example 2 which had been exposed to air for 3 hours about 150 atmosphefesing of:

(a) tri(hydrocarbyl)phosphines and whereas our novel catalyst, after a 3 hour exposure to A cyclooligomerization Process for the Pmdlletion of air, gave a conversion of 5.7 percent. A summary of the a cyclooctadiene from a 1,3-diene which comprises conresults achieved with the novel catalyst of our invention i g a ,3-diene with a catalyst system comprising after exposure to air and the results achieved with a known zerovalent nickel complexed with an organo-phosphorus catalyst after exposure to air are summarized in Table III. 40 complexing ligand and containing an excess of at least 24 TABLE III Aliquot Air Total Wt. Cat. Cone. Total Wt. Percent Solvent Soln., Exposure Cat. Moles, Ni Moles Reaction 4 V.C.H. i3 cc. Time, Hr. Comp., g. Nl/Mole Prod., g. Conversion Conversion Conversion Butadrene Phosphite 3 0 0. 378 3. 125X10- 18. 2X10 95 7. 5 91. 3 1 0 Mesltylene 3 0 0. 378 3. 125x10- 18. 2X10- 95 5. 8 75. 0 17 8 Phosphite 3 3 0. 378 3. 125X10 18. 2X10- 25 8. 9 5. 7

Mesitylene a s 0. 31s 3.125 10 1s. 2 1o- 20 12. 0 0.1 IIIIIIIIIIIII 1 4V.C.H.=vinyl eyelohexene. C.O.D.=1,3- and 1,5-cyclooetadiene. B C.D.T.=1,5,9-cyclododecatriene.

As can be seen from the preceding examples, the novel moles of said ligand per mole of nickel; said organocyclooligomerization catalyst system of our invention is phosphorus ligand being selected from the group conespecially elfective for the cyclooligomerization of 1,3- sisting of: butadiene to cyclooctadienes. The catalyst of our invention tri(hydrocarby1 )pho hine and is also unusually stable upon exposure to air and retains (b) tri(hydrocarbyl)phosphites Its effeclivene$ for mlleh longer Period of time than in which each hydrocaibyl group contains 1 to about 10 known eyeloohgomerlzation eatalysts- Furthermore, the carbon atoms and said contacting being carried out at a novel catalysts Of 0111' invention are generally more temperature of about 80 C. to about 175 C. and a preslective for the highly desired cyclooctadienes than other Sure ofup to about 150 atm here catalysts and retain this high selectivity over a wide range 5 A cyclooligomerization process f the roduction of eatelysf eoneentl'atlon- The Unexpected efficiency Of Our 0 of a cyclooctadiene from 1,3-butadiene which comprises Catalysts 15 pp 0m an itlsPection 0f the Preceding contacting 1,3-butadiene with a catalyst system comprising examples. zerovalent nickel complexed with an organo-phosphorus Although the Invention has been described in C d complexing ligand and containing an excess of at least 24 able detail with particular reference to certain preferred moles f id li d l of i k i organ-1O- embodiments thereof, variations and modifications can be phosphorus ligand b ing el ted fro the group coneffected within the spirit and scope of the invention as sisting of; e described hereinbefore and as defined in the appended t i(h d -o rb 1) hosphines and claims. (b) tri(hydrocarbyl)phosphites We clalmr in which each hydrocarbyl group contains 1 to about 10 1. A cyclooligomerization process for the production of 7 carbon atoms and said contacting being carried out at a a cyclooctadiene from a 1,3-diene which comprises contemperature of about C. to about 175 C. and a prestacting a 1,3-diene with a catalyst system comprising sure of up to about atmospheres. zerovalent nickel complexed with an organo-phosphorus 6. A cyclooligomerization catalyst system comprising complexing ligand and containing an excess of at least zerovalent nickel complexed with an organo-phosphorus 24 moles of said complexing ligand per mole of nickel. 75 complexing ligand and containing an excess of at least 24 moles of said organo-phosphorus complexing ligand per mole of nickel.

7. The catalyst system of claim 6 in which the organophosphorus complexing ligand is selected from the group consisting of:

(a) tri(hydrocarbyl)phosphines and (b) tri (hydrocarbyl phosphites.

8. A cyclooligomerization catalyst system comprising zerovalent nickel complexed with an organo-phosphorus complexing ligand and containing an excess of at least 24 moles of said ligand per mole of nickel; said organophosphorus ligand being selected from the group consisting of:

(a) tri(hydrocarbyl)phosphines and (b) tri (hydrocarbyl phosphites References Cited FOREIGN PATENTS 987,423 3/1965 Great Britain 260666 917,103 1/1963 Great Britain 260666 970,335 9/1964 Great Britain 260666 DELBERT E. GANTZ, Pw'mary Examiner.

V. OKEEFE, Assistant Examiner. 

